World number one Roger Federer lost for the first time in 24 matches when he was beaten by Slovakian Dominik Hrbaty 1-6, 7-6, 6-4 in the first round of the Cincinnati Masters on Tuesday.

Had he won, the Wimbledon and Australian Open champion, who beat Andy Roddick to win the Toronto Masters on Sunday, would have equalled the 24-match winning streak set by Pete Sampras in 1999.

"You have to do everything to be ready (for tournaments)," a weary Federer said. "It's obviously difficult to bounce back from victories.

"It may have been one tournament too much for me to keep winning, so I can't be too disappointed.

"I have had a great run, and I have a few more days off and that's the positive side to it."

It was Federer's first defeat since losing in the third round of the French Open at the end of May and came only two days after he repeated his Wimbledon final victory over world number two Roddick with a spectacular performance in Toronto.

Then, as now, the 22-year-old Swiss warned he was exhausted, which may explain why, after dominating the first set, he failed to capitalise on several good chances in the second, missing break points in the third and fifth games.

Federer then played an uneven tiebreak, following great shots with indifferent ones to lose 9-7 after over-hitting a backhand drive.

MISSED OPPORTUNITIES

In the third set the Swiss had little difficulty holding serve until the ninth game, when he again lapsed, conceding the game with a forehand drive struck uncharacteristically wide.

"It was a pity I couldn't win in two sets," Federer said. "I had chances definitely in the second set.

"I thought I played really well for one and a half sets and missed opportunities in the second set and he made me pay.

"At the start he was giving me quite a few points and missing shots but in the second and third he wasn't and played really well."

The 21st ranked Hrbaty took his chances well, both in the tiebreak and while serving out for the match without fuss, but the impression persisted that the real winner here was Federer's schedule.

The early exit will allow him more preparation time for the Olympic Games in Athens starting on August 13.

It also made defending champion Roddick favourite to win the Cincinnati title again, though he came perilously close to a first round defeat before overcoming Max Mirnyi of Belarus 6-7, 7-6, 6-3.

The American was a set down and trailed 5-4 in the second set tiebreaker with two Mirnyi serves to come.

However, just when Roddick seemed out of it he produced a pair of great returns of serve to turn the tiebreak back in his favour.

"He definitely could have closed me out, and at that point I felt I definitely deserved to lose," admitted the champion who found the conditions much quicker than in Toronto.

But Roddick appeared to want to avoid defeat more than Federer.

Often he fretted and fumed, once he whacked himself on the head with his racket and on another occasion knocked over a television microphone at the back of the court.

His desire to succeed may have been crucial in helping him survive for a third meeting with Germany' Nicolas Kiefer in as many weeks.

On Tuesday, Federer became the quickest qualifier for the end of year Tennis Masters Cup in Houston following his runaway success in 2004. As well as his two Grand Slams, he has also won three ATP Masters Series titles.